Reproducer for phonographs



B. B. B Loon. REPBODUCER FOR PHONOGBAPHS. APPLICATION FILED JUNE 24| |920- Patented Dec. 5,1922

w 10 1E f3 8 Patented Dec. 5, 1922.

UNITED sTAiEsPATENT OFFICE.

BURR B. BLOOD, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO JEWEL PHONOPARTS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION 0F ILLINOIS.

REPRODUCER FOR PHONOGRAPHS.

Application filed June 24, 1920. Serial No. 391,298.

To all 'whom it may concern:

Be it known that I, BURR B. BLOOD, a citizeil of the United States, and a resident of Chicago, in the countyof Cook and State of Illinois, have invented a certain new and useful Improvement in Reproducers for Phonographs, of which the following is a description, reference being had to the accompanying drawing, which forms a part of my specification.

- My invention relates to an improvement in reproducers or sound-boxes for phonographs` and pertains more especially to the flexible diaphragm and its mounting; the object of the invention being to provide a construction wherein the diaphragm will have a greater vibrating portion and a more uniform flexing area whereby the tone quality of the reproducer will be greatly enhanced. i

The construction and its advantages will be readily comprehended from the following detailed description of the accompanying drawing wherein Figure 1 is a front elevation of my imtive, of the flexible diaphragm, illustratingv the lower or inner side thereof.

My invention contemplates a flexible diaphragm, preferably made of a chemical composition rather than of mica; and in the specific exemplification of the invention it comprises a diaphragm or disc 10 ofa diameter commensurate with the inside diameter of the casing-ring or member 11 of the reproducer-shell. The diaphragm is of suitable thickness but with a portion somewhat removed from the periphery made of less thickness, as indicated at 12, see Figures 2 and 4. In other words, the diaphragm 10, in the preferred form, is of equal thickness throughout, except for the reduced portion 12 which is adapted to come within the area or circle described by the inwardly disposed peripheral flange 13 of the ring or front shell portion 11 of the reproducer. The reduced portion 12 in the construction illustrated is shown formed by providing the lower or what may be termed the inner surface of the diaphragm, with an annular groove of comparative width and thereby providing an annular central portion 14 to which the stylus bar 15 is secured in the usual manner. f

By providing the diaphragm with the kerfed or reduced portion 12 at the place indicated, it leaves a marginal portion 16 on the diaphragm preferably ofequal thickness with the central portion 14; the marginal portion 16 being of width substantially equal to the width of the kerfed or flanged portion of the ring or shell section 11. The marginal portion 16 is intended to be clamped between the rear wall or main section 17 of the reproducer and the front or ring section 11; the diaphragm being preferably clamped and held in place by means of suitable rubber rings or gaskets 18, 18 disposed 'on opposite sides of the flexible diaphragm; that is to say, one rubber ring or gasket 18 is arranged on the rear wall or main section 17 of the reproducer, while the other rubber ring or gasket 18 is mounted beneath the Harige 13 of the ring section 11 of the reproducer, so that when y the ring section 11 is properly secured to the back or main section 17, by means of the screws 19the rubber rings or gaskets 18 will be compressed against the flexible diaphragm 10.

The marginal portion 16 of the flexible diaphragm is of width to adapt it to extend beyond the point where the rubber rings or gaskets 18, 18 contact therewith and therefore extend into the kerfed portion of the ring or shell section 11; and this marginal portion 16, at a point intermediate of the rubber rings or gaskets 18, and the periphery thereof, preferably has its lower surface provided with an annular groove 20, see Figure 4. The groove 20 is shown as preferably V-shape in cross-section and is disposed at a point where it will register with and therefore receive an annular rib 21, also preferably V-shape in cross-section, which is formed integral with the rear wall or main section 17 of the reproducer.

In has been found in practice, that the flexible diaphragm, especially where it is made comparatively thin, has a tendency to buckle when the rubber rings or gaskets are placed under compression; this buckling 0r 'bowing 10i .the diaphragm, of Course; greatly interfering with its rfree vibratory or flexing action which is Ainduced by the vibration of the stylus bar. It is apparent that the buckling or bowing of the diaphragm will induce a much stiffer action ,therefore result in `a considerable loss o-f the finer tones or yibrations. In providing the flexible ,diaphragm with the groove 20 and one ,shell or section of the reproducer with ,a correspondingly formed rib,

vto register with and become seated in the grove `of the diaphragm, any tendency or possibility of the fiie'xible diaphragm `to buckle orbecome ydistorted will be entirely eliminated', 4.the rib 2l will prevent any movement or crowding of the flexible diaphragm into the area described by the inner Acircumference of the ring section of the reproducer.

'in the particular eXempliiicat-ion, the screw-receiving ,holes 22 formed in the rear wall section .of the reproducer are shown -lo cated at ,points registering with the .annular rib 21, so ,that the y,dieph ragm .,i-s likewise illustrated provided with screw-receiving holes 2,3 for the 2passage of the screws i9 whereby the ,two ,shell sections of the reproducer lare ,secured together. It is apparent, however, that fthe' screw-receiving ,openings 2 2 ,and 23 in the rear wall section 17 and iieizible diaphragm 1.0, respectively, need not be arranged at the ,particular point indicated and funthermore the `:enact formation 4of the reproducer she-ll sections niay be somewhat varied from the 4construction shown ;l while at .the .same .time 4,the reduced or more readily fleXing portion .of Ethe flexible diaphragm may also .be Yobtained in a somewhat different -inanner Vfrom that shown and described` These modifications .and other yslight modiiications may be made in details .of construe tion without departing from the spirit ,ofmy invention Having thus .described my invention, what I ,desire to tsecure by Letters -Patent- ,is

l. 1n a .reproducer of ,the character ,described, a 4casing composed cfa main yOr back member ,and ,a front .or ring member, one Aof said members being provided with an annular rib, both members being ,removably secured together, ,and a flexible diaphragm, the peripheral margin whereof is adapted to be clamped between the 4two members 1of the casing, the peripheral margin of the diaphragm adapted to be clamped between the Casing-members beine' rforided withal-.I1 e11- nular' groove Kof coniiguration substantially similarV to the cross sectional configuration of the annular rib on said casing member and adapted to receive the said annular rib.

2. A reproducer ofthe character described, comprising a casing composed of a main or back member and front or ring mem-loer provided with a kerf or under-,cut and adapted to be removably secured Ito the ina-in member, one of said members adjacent `the periphery thereof being provided with a projection on its ,inner sur-face, and .a flexible diaphragm .adapted to extend into .said kerf or undencnt .of the ring member .and lto 'be clamped lbetween both casing members, the

marginal portion of the diaphragm being recessed to receive the projection fon the inner surface of the casing-member whereby buckling or crowd-ing of the diaphrageinD within the ring member is prevented. l

3. In a reproducer of the character described, a ,casing composed ,of .a main or back member lprovided with an `annular rib Jadja cent the periphery thereof :and ,a frontor ring member, the latter 'being provided with an inwardly disposed annular flange and with a diaphragm-receiving recess, the two members 'beine removably secured together, a flexible diap ragm .adapted to be seated in the recess of said ringmember .and `to `be clamped between both casing members, the iiexible diaphragm adjacent its ,perimeter provided with an .annular groove adapted to receive the .annular rib yformed on the main member ofthe casing.

4. .A reproducer of the characterdescribed, comprising a ,casing vcomposed of a main or back menrler provided with an .annular rib, Vesljiape in cross-section, disposed adjacent the periphery thereof, and a ring mem'- ber removably .secured `to fthe :main member, a @flexible diaphragm Vadapted to :be clamped between the .casing-members, and provided in its marginal .portion with an annular groove, 'V-shape 'in cross-section, adapted to receive the annular .rib on the main member of the casing whereby 'buckling of the diaphragm within @the ring inembei` of the casing will be prevented. i

' BURR B. BLOOD.

1llitnesses: 1

G. HnIDMAN, F. A. Ehemann. 

